1. Field
The present disclosure relates to a mask frame assembly, a method of manufacturing the same, and a method of manufacturing an organic light-emitting display device using the mask frame assembly.
2. Description of the Related Technology
Organic light-emitting display devices have been spotlighted as next-generation display devices because of their light weight, thin profile, wide viewing angle, fast response time, and low power consumption.
An organic light-emitting display device generally includes a first electrode formed in a predetermined pattern on a transparent insulating substrate, an organic film formed on the first electrode, where the film may be formed by using vacuum deposition, and a second electrode formed on a top surface of the organic film.
The first electrode may be patterned by using a method of wet etching, such as photolithography. However, if the organic film is an organic light-emitting layer for creating a predetermined color image, the organic film and the second electrode formed on the organic film may not be patterned by wet etching. This is because when the organic film is formed and then wet etching is used, moisture generated due to the wet etching penetrates the organic film or remains on the organic film, thereby degrading the performance and the lifetime of the organic light-emitting display device.
Deposition has been used in attempts to solve the problem. In order to manufacture an organic light-emitting display device by using deposition, a fine metal mask (FMM) having the same pattern as a pattern of a thin film to be formed on a substrate is aligned, and a raw material of the thin film is deposited, to form the thin film having a desired pattern.
As the FMM gets larger, an error in etching for forming a pattern may be increased, and sagging of a central portion due to the weight may become serious. Accordingly, divided masks which are obtained by dividing a mask in a plurality of stripe shapes and attaching the same to a frame have been used. However, the divided masks may also undergo some sagging. To address the sagging, when the divided masks are attached to the frame, they may be welded to the frame while being stretched tight in a longitudinal direction.
However, if the divided masks are so welded, while a tensile force is applied in the longitudinal direction in which the divided masks is stretched, a contractile force is applied in a width direction, thereby causing wave-shaped wrinkles in the divided masks. Once such wrinkles occur, since some portions of the divided masks fail to closely contact the substrate, precise patterning may not be achieved.